With his teammate Antonelli out of the running, Russell showed why Mercedes is such a big favourite at the Baku track as he went nearly a second faster than anyone else.
Ferrari's Charles Leclerc was .837 of a second off the pace in second while Australian driver Oscar Piastri was third-fastest for McLaren, a further .001 back.
That was a big turnaround for Piastri after McLaren had resorted to using cable ties to hold together parts of the car's bodywork in a chaotic Friday practice.
"It's been a little bit of a tricky one for us, but it's not the first time this year," the Australian said.
"I feel like we get to qualifying, we take all the fuel out and the car just comes alive more."
Isack Hadjar was fourth for Red Bull on his return from injury and no one else got within a second of Russell.
It is the first pole for the British driver since the Austrian Grand Prix in June, which was also his most recent win. The long straight at Baku favours Mercedes' engine and car design.
"It has been a while since I have been on pole, so it definitely feels good," Russell said.
"It is probably the biggest (pole) margin of my whole career, even in my Formula Two and Formula Three days, and that felt really sweet.
"We are in a great place to go for the win, but this is Baku and anything can happen."
Antonelli is set to start Saturday's race in 16th place on the grid after he clipped the wall and damaged a wheel and his suspension in the first part of qualifying.
The Mercedes driver's previous lap time was enough to reach the second part of qualifying but he was unable to continue.
Nevertheless, Russell insisted "you can't discount Kimi" for Saturday's race after Antonelli won from 19th on the grid at his home Italian Grand Prix earlier this month.
The 20-year-old Antonelli leads Russell by 81 points in the overall drivers' rankings.
- with PA
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